Apparatus and method for surface treatment to substrate

ABSTRACT

An apparatus and a method for surface treatment of substrates whereby the quality of substrates can be maintained by preventing excessive plasma treatment of substrates. In carrying out the plasma treatment on a surface of the substrate in a reaction chamber, there are provided an emission spectroscopic analysis device or a mass analyzer, and a controller, so that the energy of ions in plasma is controlled to decrease when, e.g., bromine included in the substrate is detected, and the surface treatment to the substrate is controlled to stop when the removal of impurities of the substrate is detected to end. The bromine once separated from the substrate is prevented from adhering again to the substrate and corroding the substrate. Moreover, ions are prevented from being excessively irradiated to the substrate when the removal of impurities ends, thereby reducing damage to the substrate.

This is a divisional application of Ser. No. 10/233,440 filed Sep. 4,2002.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for executing surfacetreatment such as cleaning, modifying or the like on substrate surfacesby plasma, and a method for substrate surface treatment carried out bythe substrate surface treatment apparatus.

High-packaging density has been required in the field of a mountingtechnique in accordance with miniaturization and multifunction ofelectronic devices. Consequently, connections between elements andsubstrates should be carried out on a remarkably fine scale, andmounting with a higher degree of reliability is being required. Therecurrently is a method of modifying substrate surfaces by plasma, i.e.,plasma treatment as one example for securing the reliability. Forinstance, the plasma treatment can remove an organic contaminantadhering to the substrate surface, and the bonding strength between agold electrode and a wire in the case of wire bonding can be improvedwhen an inorganic substance such as nickel hydroxide or the likedeposited on an electrode face as a bonding face formed of copper,nickel, and gold on a printed board is removed by the sputtering actionof argon plasma. Also in the case where an IC is to be bonded to a leadelectrode on a polyimide film substrate via an ACF (anisotropicconductive film), the bonding strength between the polyimide film andthe ACF can be improved through activation of a surface of the polyimidefilm substrate by irradiating oxygen plasma to the film before bonding.Moreover, the plasma treatment carried out on the substrate improves thefluidity of a sealing resin on the substrate and the adhesion betweenthe substrate and the sealing resin.

An example of the plasma treatment method referred to above will bedescribed below with reference to the drawing FIGS. 3-5.

FIG. 3 roughly shows the configuration of a conventional apparatus 20for surface treatment of mounting substrates, in which a reactionchamber 1 being grounded is provided with a gas introduction port 2 anda vacuum exhaust port 3. A RF electrode 5 is arranged in the reactionchamber 1 via an insulating ring 4 to a side wall of the reactionchamber 1. The RF electrode 5 has a constitution on which a mountingsubstrate 6 can be placed. An opposed electrode 7 is arranged in thereaction chamber 1 so as to face the RF electrode 5 and is grounded. ARF(Radio-Frequency) is applied to the RF electrode 5 by a RF supplysource 8 through a matching tuner (not shown) and a RF power supplypart. O-rings (not shown) are interposed between the RF electrode 5 andthe insulating ring 4 and between the insulating ring 4 and the sidewall of the reaction chamber 1. For preventing the O-rings from beingheated to 200° C. or higher and maintaining the reaction chamber 1 invacuum, a cooling groove 9 where a cooling water flows is formed in theside wall of the reaction chamber 1.

The surface treatment method to mounting substrates carried out by theabove-constituted surface treatment apparatus 20 will be describedhereinbelow in an example in which an argon gas is used for substratesbefore wire bonding.

The substrate 6, before being subjected to wire bonding, is placed onthe RF electrode 5. While a degree of vacuum in the reaction chamber 1is kept to be 30 Pa with 50SCCM (standard cc/min) of the argon gas beingsupplied from the gas introduction port 2, a RF(Radio-Frequency) of 200W is applied to the RF electrode 5, thereby generating plasma. Argonions in the plasma are irradiated onto a face of the substrate 6 exposedin the plasma. The substrate 6 is formed of glass cloth epoxy resin. Anelectrode 10 formed on the surface of the substrate 6 is constituted ofthree layers of a copper layer 11 having a film thickness of 35 μm, anickel layer 12 having a film thickness of 3 μm and a gold layer 13having a film thickness of 0.05 μm as shown in FIG. 4. The undercoatnickel 12 is moved onto a surface of the gold 13 through a heat processor the like, whereby nickel hydroxide or the like is deposited. Thenickel hydroxide is sputtered and removed by the irradiation of argonions. The surface of the gold 13 is cleaned accordingly.

FIG. 5 is a schematic diagram of a case in which a silicon chip IC 16 isbonded via an ACF (anisotropic conductive film) 15 to a polyimide filmsubstrate 14. As shown in FIG. 5, electrodes 18 of the IC 16 are bondedvia the ACF 15 composed of a resin containing conductive particles toelectrode parts 17 on the polyimide film substrate 14. A surfacetreatment method for the polyimide film substrate 14 having the aboveconstitution will be described below.

The polyimide film substrate 14 is placed on the RF electrode 5. ARF(Radio-Frequency) of 200 W is applied to the RF electrode 5 while adegree of vacuum in the vacuum chamber 1 is maintained at 30 Pa with50SCCM of an oxygen gas supplied from the gas introduction port 2. As aresult, plasma is generated. Oxygen radicals or oxygen ions present inthe plasma are irradiated onto a surface of the polyimide film substrate14 exposed in the plasma. The oxygen radicals react with contaminationorganic substances adhering on the polyimide film substrate 14, wherebythe contamination organic substances are decomposed to be sublimationcompounds such as CO₂ or the like and then removed. Further, functionalgroups such as C═O, COOH and the like are generated on the surface ofthe polyimide film substrate 14, activating the surface of the polyimidefilm substrate. The bonding strength between the polyimide filmsubstrate 14 and the ACF 15 is improved accordingly.

In the case of polyimide film substrate 14, residual ions of chlorine orthe like are left yet on the polyimide film substrate 14 when theapparatus receives the polyimide film substrate 14. The reason for thisis that hydrochloric acid is used as one of components of a platingsolution for forming a pattern of the electrodes 17 on the polyimidefilm substrate 14 by plating, and, for example, chlorine ions are leftif the substrate is not fully cleaned by water after the pattern isformed. In the event that the IC 16 is connected with the use of the ACF15 to the polyimide film substrate 14 having the residual ions, theresidual ions cause corrosion and electrical failures such as ionmigration, etc. As such, the plasma treatment is carried out to removethe chlorine ions.

However, if the plasma treatment is carried out on the substrate 6before being subjected to wire bonding, not only the organiccontaminant, inorganic substance, or the like, but the substrate 6 issputtered by argon ions simultaneously. In the case of the substrate 6formed of glass cloth epoxy resin, Br (bromine) included in thesubstrate 6 adheres again to the substrate after being separated fromthe substrate 6 by the plasma treatment. In the case of the Br adheringto the electrode 10, the trouble is that the Br adhering on theelectrode 10 reacts with moisture in the air and becomes HOBr or HBrwhen the substrate 6 is exposed to the atmosphere, which causescorrosion of the electrode 10.

When the plasma treatment is carried out with the aim of removingresidual ions adhering to the polyimide film substrate 14, since thereis no means for observing whether or not the residual ions are actuallyremoved, the plasma treatment may be executed to an excessive stage inorder to perfectly remove the residual ions. Thus the trouble is thatthe excessive plasma treatment may also damage the polyimide filmsubstrate 14.

SUMMARY OF THE INVENTION

Accordingly, the present invention is devised to solve theabove-discussed problems inherent in the conventional art and an objectof the present invention is to provide an apparatus and a method forsurface treatment to substrates whereby the substrate quality can bemaintained by preventing an excessive plasma treatment to thesubstrates.

In accomplishing the above objective, according to a first aspect of thepresent invention, there is provided a substrate surface treatmentapparatus for executing surface treatment of a substrate arranged in areaction chamber by ions in plasma generated in the reaction chamber,which comprises:

a detecting device arranged adjacent to the reaction chamber fordetecting at least whether or not components constituting the substrateare separated from the substrate, or whether or not impurities adheringto a surface of the substrate are removed by the surface treatment; and

a controller connected to the detecting device for reducing an energy ofthe ions in the plasma on the basis of the detected information by thedetecting device when the separation of components is brought about, andfor terminating the surface treatment on the basis of the detectedinformation by the detecting device when the removal of impurities ends.

The substrate surface treatment apparatus may be further provided with aplasma generating device including electrodes arranged in the reactionchamber for generating the plasma and a power supply unit for supplyingelectricity to the electrodes, and

a vacuum degree adjusting device connected to the reaction chamber foradjusting a degree of vacuum in the reaction chamber.

The controller controls operations of the power supply unit and thevacuum degree adjusting device on the basis of the detected informationby the detecting device so as to control reduction of the energy of theions and to end the surface treatment.

The above detecting device may be comprised of a spectroscopic analyzerfor conducting spectral observation of light generated by the plasma anddetecting the components and the impurities of the substrate on thebasis of the observation.

The above detecting device may be comprised of a mass analyzer foranalyzing gas elements in the reaction chamber and detecting thecomponents and the impurities of the substrate on the basis of the gasanalysis.

The components of the substrate to be detected by the detecting devicemay be bromine (Br).

The impurities to be detected by the detecting device may be chlorine.

According to a second aspect of the present invention, there is provideda substrate surface treatment method for executing surface treatment ofa substrate arranged in a reaction chamber by ions in plasma generatedin the reaction chamber, which comprises:

detecting at least either whether or not components constituting thesubstrate are separated from the substrate by the surface treatment, orwhether or not impurities adhering to a surface of the substrate areremoved by the surface treatment; and

controlling on a basis of the detected information an energy of the ionsin the plasma to reduce when the separation of components is detected totake place and the surface treatment to end when the removal ofimpurities is detected to end.

By the above construction of the aspects of the present invention, thereare provided the detecting device and the controller, so that the energyof ions in the plasma is controlled to decrease when the constituentseparated from the substrate is detected, and the surface treatment tothe substrate is controlled to terminate when the completion of removingimpurities adhering to the substrate is detected. In the arrangement asabove, the constituent of the substrate can be prevented from separatingand scattering from the substrate. Therefore the phenomenon that theseparated constituent from the substrate adheres again to the substrateand the redeposit of the separated constituent causes corrosion to thesubstrate is avoided. Furthermore, the ions are prevented fromexcessively irradiating the substrate when the removal of impurities iscompleted, therefore reducing damage to the substrate.

The first embodiment and the second embodiment of the present inventionenable the prevention of excessive plasma treatment of substrates whilemaintaining the quality of the substrates.

When the plasma generating device and the vacuum degree adjusting deviceare provided additionally, the controller can control the power supplyunit installed at the plasma generating device and the vacuum degreeadjusting device on the basis of detected information by the detectingdevice. In other words, the power to be supplied to the electrode in theplasma generating device is reduced by controlling the power supplyunit, so that the energy of ions in the plasma can be decreased. As aresult, the efficiency for sputtering can be lowered. Moreover, acollision probability between gas molecules and ions in the reactionchamber increases by raising the pressure in the reaction chamber by thevacuum degree adjusting device, and eventually the energy of the ionscan be decreased. Furthermore, the plasma treatment can be stopped by,e.g., stopping the power supply.

When the spectroscopic analyzer is used as the detecting device, thedetecting device can be arranged on the outside of the reaction chamber,and the whole construction of the substrate surface treatment apparatusis simplified.

When the mass analyzer is used as the detecting device, the constituentand impurities of the substrate can be detected with a higher degree ofaccuracy than by the spectroscopic analyzer, thus enabling the qualityof the substrate to be maintained at a high level.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings in which:

FIG. 1 is a schematic diagram of the configuration of a surfacetreatment apparatus for substrates according to a first embodiment ofthe present invention;

FIG. 2 is a schematic diagram of the configuration of a surfacetreatment apparatus for substrates according to a second embodiment ofthe present invention;

FIG. 3 is a schematic diagram of the configuration of a conventionalsurface treatment apparatus for substrates;

FIG. 4 is a diagram showing the constitution of a substrate electrode;and

FIG. 5 is a diagram for briefly explaining bonding when an IC chip isbonded via an ACF to a film substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An apparatus for surface treatment of substrates and a method forsurface treatment of substrates which is carried out by the apparatusaccording to the preferred embodiments of the present invention will bedescribed below with reference to the attached drawings. It is to be isnoted that like parts are designated by like reference numeralsthroughout the accompanying drawings.

First Embodiment

FIG. 1 is a schematic diagram showing the construction of a substratesurface treatment apparatus 101 according to a first embodiment. Roughlyspeaking, the apparatus 101 has a reaction chamber 110, a plasmagenerating device 120, a vacuum degree adjusting device 130, a detectingdevice 140, and a controller 150. The reaction chamber 110 in which asubstrate 109 is stored is a vessel for carrying out surface treatmentby plasma to the substrate 109, which comprises a reaction gasintroduction port 111, an exhaust port 112 and an observation window113, and is grounded. To the reaction gas introduction port 111 isconnected a reaction gas supply unit 161 which supplies a reaction gasfor generating desired ions into the reaction chamber 110 via thereaction gas introduction port 111. The operation of the reaction gassupply unit 161 is controlled by the controller 150.

Inside the reaction chamber 110, there is arranged an electrode 121connected via an insulating ring 162 to a side wall 110 a of thereaction chamber 110. The electrode 121 is constituted so that thesubstrate 109 can be placed on the electrode 121. O-rings are interposedbetween the electrode 121 and the insulating ring 162 and between theinsulating ring 162 and the side wall 110 a, whereby the reactionchamber 110 is kept in vacuum. Moreover, a cooling groove 163 forpassing a coolant, e.g., cooling water, is formed in the side wall 110 aso as to prevent the O-rings from being heated to 200° C. or more. Acoolant supply unit 164 which is controlled in operation by thecontroller 150 for supplying the coolant, i.e., cooling water in thisembodiment is connected to the cooling groove 163.

Also in the reaction chamber 110, an opposed electrode 122, which isgrounded, is arranged opposite to the electrode 121. ARF(Radio-Frequency) is applied to the electrode 121 by a power supplyunit 123 including a matching tuner and a RF power supply part. Theplasma generating device 120 is constituted of the electrode 121, theopposed electrode 122 and the power supply unit 123. The operation ofthe power supply unit 123 is controlled by the controller 150. Plasmacan be generated between the electrode 121 and the opposed electrode 122by supplying the RF to the electrode 121 in the reaction chamber 110 towhich a predetermined reaction gas is supplied in a vacuum state.

According to the embodiment, an emission spectroscopic analysis device141 is arranged as an example of a spectroscopic analyzer and thedetecting device 140 for observing a state of the plasma in the reactionchamber 110 from the outside of the apparatus, and more specifically,for observing an emission state of the plasma from the outside of theapparatus. The emission spectroscopic analysis device 141 is disposedadjacent to the observation window 113. Although described in detaillater, the detecting device 140 detects at least either whether or notcomponents constituting the substrate 109 are separated from thesubstrate 109 by the surface treatment carried out on the substrate 109with the utilization of the plasma, or whether or not impuritiesadhering to a surface of the substrate 109 are removed by the surfacetreatment.

The vacuum degree adjusting device 130 connected to the reaction chamber110 is a device for adjusting the degree of vacuum in the reactionchamber 110. The vacuum degree adjusting device 130 has a valve 131 forshutting the inside from the outside of the reaction chamber 110, moreprecisely, for shutting the inside from a vacuum pump 133 to bedescribed below, a valve switch 132 for controlling an opening degree ofthe valve 131, and the vacuum pump 133 for turning the interior of thereaction chamber 110 to vacuum via the valve 131. As will be detailedlater, the vacuum degree adjusting device 130 adjusts the degree ofvacuum inside the reaction chamber 110 in accordance with a controlsignal sent from the controller 150 on the basis of detected informationsent from the detecting device 140, namely, the emission spectroscopicanalysis device 141 in the embodiment to the controller 150.Specifically, the control signal is supplied to the valve switch 132,whereby the valve 131 is opened at the opening degree conforming to thecontrol signal. The degree of vacuum in the reaction chamber 110 isadjusted in this manner.

Operation, i.e., the surface treatment method in the above-constitutedsubstrate surface treatment apparatus 101 will be described below. Thecontroller 150 carries out control related to the substrate surfacetreatment method. The following description is based on a state in whichthe substrate 109 is already placed on the electrode 121.

While the air in the reaction chamber 110 is discharged by the vacuumpump 133, 50SCCM of an argon gas is supplied from the reaction gasintroduction port 111 by the reaction gas supply unit 161 so that thereaction chamber 110 is held in a degree of vacuum of 30 Pa. In thisstate, 200 W RF(Radio-Frequency) is applied to the electrode 121 fromthe power supply unit 123 to generate plasma between the electrode 121and the opposed electrode 122 in the reaction chamber 110. Argon ionspresent in the plasma are irradiated to the surface of the substrate 109exposed in the plasma. Although nickel hydroxide or the like isdeposited onto a surface of the electrode 10, which is formed of gold onthe substrate 109 in the same arrangement as that described withreference to FIG. 4, through a heat process or the like as discussed inthe “BACKGROUND OF THE INVENTION”, the nickel hydroxide or the like isremoved by the sputtering action because of the irradiation of argonions, and therefore, the surface of the electrode 10 formed of gold iscleaned.

At this time, the surface of the substrate 109 except the electrode 10is also sputtered by the irradiation of argon ions. In the case wherethe substrate 109 is formed of glass cloth epoxy resin, Br (bromine) asone of components constituting the substrate 109 is sputtered as well,emitted into the reaction chamber 110. Thus, there is the apprehensionthat the emitted Br will again adhere to the surface of the substrate109.

Meanwhile, according to the present embodiment, the plasma state in thereaction chamber 110 is monitored at all times through the observationwindow 113 by the emission spectroscopic analysis device 141. Theemission spectroscopic analysis device 141 sends a signal to thecontroller 150 at a time point when an emission spectrum of the Br isobserved. The controller 150 in return controls and adjusts the powersupply unit 123 and the valve switch 132 to reduce the energy of argonions in the plasma to prevent the Br from being sputtered. Morespecifically, the controller 150 decreases the electric power to besupplied from the power supply unit 123 to the electrode 121 and alsodrives the valve 131 in a direction to close the valve to raise thepressure in the reaction chamber 110. Since the energy of argon ions isreduced by decreasing the electric power, the efficiency for sputteringcan be deteriorated. At the same time, a collision probability betweengas molecules and the argon ions in the reaction chamber 110 isincreased by raising the pressure, and eventually the energy of argonions is reduced. Thus, the sputtering efficiency can be decreased.Accordingly, only the nickel hydroxide deposited on the electrode 10 ofthe substrate 109 can be removed by the sputtering action through theirradiation of argon ions, while the Br contained in the substrate 109is prevented from being sputtered.

The sputtering efficiency to the nickel hydroxide is deteriorated by thereduction in the energy of argon ions as above. But, where the nickelhydroxide is deposited is the surface of the electrode 10 as mentionedabove, and therefore the nickel hydroxide is sputtered with priority bythe irradiation of argon ions. In contrast, since the Br is included inthe substrate 109, the amount of Br to be sputtered is relatively small.That is, the sequence of the above operations is based on the idea thatthe nickel hydroxide has been removed as much as possible before the Bris emitted from the substrate 109.

Since the nickel hydroxide can be removed from the surface of the goldelectrode 10 of the substrate 109, the bonding strength between the goldelectrode 10 and a wire can be improved when the gold electrode 10 is tobe wire bonded.

According to the embodiment as described hereinabove, in processing thesubstrate 109 formed of glass cloth epoxy resin by argon plasma, theplasma state in the reaction chamber 110 is always monitored through theobservation window 113 by the emission spectroscopic analysis device141, and the controller 150 controls the power supply unit 123 and thevalve switch 132 to adjust so as not to sputter the Br when the emissionspectrum of the Br is observed. Therefore, only the nickel hydroxidedeposited on the gold electrode 10 of the substrate 109 can be removedby irradiating argon ions while the Br as a constituent of the substrate109 is prevented from scattering. In consequence of this, the phenomenonthat the sputtered Br adheres again to the substrate 6 does not arise,and the conventional trouble that the Br and the moisture in the airreact with each other when the substrate 6 having the Br adhering to theelectrode 10 is exposed to the atmosphere, thereby forming HOBr or HBr,does not arise. Therefore, the corrosion of the electrode 10 of thesubstrate 109 can be prevented.

In the present embodiment, the controller 150 controls both of the powersupply unit 123 and the valve switch 132 when the emission spectrum ofthe Br is observed. However, the aforementioned effect is obtained bycontrolling at least one of the power supply unit 123 and the valveswitch 132 as is apparent from the foregoing description.

The substrate 109 is formed of glass cloth epoxy resin in the abovedescription. Hereinbelow will be discussed the substrate 109 formed of apolyimide film.

As is described in the “BACKGROUND OF THE INVENTION”, in the case of thesubstrate 109 formed of a polyimide film, chlorine ions are sometimesleft as an example of impurities on the surface of the substrate 109 ifcleaning at a manufacturing time of the substrate is insufficient. Forremoving the chlorine ions, an oxygen gas is supplied by 50SCCM into thereaction chamber 110 through the reaction gas introduction port 111 bythe reaction gas supply unit 161. While the degree of vacuum in thereaction chamber 110 is maintained at 30 Pa, 200 W RF(Radio-Frequency)is applied to the electrode 121, thereby generating plasma. Oxygen ionspresent in the plasma are irradiated onto the surface of the substrate109 exposed in the plasma, which sputter and remove residual chlorineions on the surface of the substrate 109.

In the meantime, the plasma state in the reaction chamber 110 ismonitored at all times by the emission spectroscopic analysis device 141through the observation window 113. The emission spectroscopic analysisdevice 141 observes an emission spectrum of chlorine. At a time pointwhen the removal of impurities terminates, that is, the emissionspectrum of chlorine disappears or the emission spectrum of chlorinedecreases to a level where no trouble is substantially brought about,the emission spectroscopic analysis device 141 sends a signal to thecontroller 150, and the controller 150 controls the power supply unit123, the valve switch 132 and the reaction gas supply unit 161 to stopthe plasma treatment.

Since the chlorine ions remaining at the substrate 109 formed of thepolyimide film can be removed in the manner as above, the problems ofcorrosion due to residual ions, electrical failures such as ionmigration or the like, which are caused by connecting the IC with theuse of ACF in a state in which chlorine ions remain, can be prevented.

In addition, by observing the emission spectrum of chlorine by theemission spectroscopic analysis device 141, the plasma treatment of thesubstrate 109 is stopped when chlorine as an impurity is removed.Therefore, chlorine ions remaining at the substrate 109 can be removedwhile the effect of oxygen ions to the substrate 109 is restricted to aminimum. At the same time, since the substrate 109 is formed ofpolyimide, an organic contaminant at the polyimide surface can beremoved by the oxygen radicals and oxygen ions as described in the“BACKGROUND OF THE INVENTION”, and also functional groups such as C═O,COOH, etc. are formed on the surface, thereby activating the surface ofthe substrate 109. The bonding strength between the substrate and theACF is improved accordingly.

Second Embodiment

The above substrate surface treatment apparatus 101 is exemplified inthe arrangement of using the emission spectroscopic analysis device 141as the detecting device 140 as shown in FIG. 1. The detecting device 140is not limited to the emission spectroscopic analysis device, and a massanalyzer 142 may be employed as will be described below with referenceto FIG. 2.

A substrate surface treatment apparatus 102 indicated in FIG. 2 isconstituted including the mass analyzer 142 in place of the emissionspectroscopic analysis device 141 installed in the foregoing substratesurface treatment apparatus 101. The same parts in the substrate surfacetreatment apparatus 102 as those of the substrate surface treatmentapparatus 101 are designated by the same reference numerals, and thusare omitted from the description. Only different parts will be discussedbelow.

Since the emission spectroscopic analysis device 141 is eliminated fromthe substrate surface treatment apparatus 102, no observation window 113is formed in the reaction chamber 110. On the other hand, the massanalyzer 142 is mounted on the exhaust port 112 communicating with thevalve 131 from the reaction chamber 110 so as to analyze a plurality ofgas elements present at the exhaust port 112, that is, in the reactionchamber 110. The mass analyzer 142 is connected to the controller 150.

The operation, i.e., surface treatment method in the substrate surfacetreatment apparatus 102 constructed as above, will be describedhereinbelow. Comparing the substrate surface treatment method in theapparatus 102 with that in the apparatus 101, only the manner ofdetecting a detection object in the reaction chamber 110 is differentwhile the operation and effect obtained in the apparatus 102 arefundamentally equal to the operation and effect exerted in the apparatus101. Therefore, an operation of detecting the detection object will beprimarily described below, with the rest being omitted from thedescription or roughly described.

In the case where the substrate 109 is formed of the glass cloth epoxyresin material, an argon gas is supplied by 50SCCM into the reactionchamber 110 from the reaction gas introduction port 111 while the air inthe reaction chamber 110 is discharged by the vacuum pump 133. In astate with the reaction chamber maintained at 30 Pa of the degree ofvacuum, 200 W RF is applied to the electrode 121 thereby generatingplasma. Similar to the case of the substrate surface treatment apparatus101, argon ions in the plasma are irradiated to the surface of thesubstrate 109, and nickel hydroxide or the like deposited on the surfaceof the gold electrode 10 is removed by sputtering. On the other hand, aplurality of kinds of gases present in the reaction chamber 110 aremonitored by the mass analyzer 142 at all times after the reactionchamber 110 reaches a specified degree of vacuum or when the plasma isgenerated. The mass analyzer 142 sends a signal to the controller 150when the element Br, separated from the substrate 109 formed of theglass cloth epoxy resin material and emitted to the reaction chamber110, is observed. Based on the supply of the signal, the controller 150controls the power supply unit 123 and the valve switch 132 to preventthe Br from being sputtered. Accordingly, only the nickel hydroxidedeposited on the gold electrode 10 of the substrate 109 can be removedby the irradiation of argon ions without scattering the Br as aconstituent of the substrate 109. Corrosion of the electrode 10 causedby the Br can be thus prevented.

The controller 150 controls both of the power supply unit 123 and thevalve switch 132 when the mass analyzer 142 detects the Br. However, theabove-described effect can be obtained by controlling at least one ofthe power supply unit 123 and the valve switch 132.

If the substrate 109 is formed of a polyimide film, in order toeliminate residual chlorine ions, the oxygen gas is supplied by 50SCCMinto the reaction chamber 110 while the air in the reaction chamber 110is discharged by the vacuum pump 133 so that the reaction chamber 110 ismaintained at the degree of vacuum of 30 Pa. In this state, 200 W RF isapplied to the electrode 121, thereby generating plasma. Oxygen ionspresent in the plasma are irradiated onto the surface of the substrate109 exposed in the plasma. Residual chlorine ions on the surface of thesubstrate 109 are hence removed.

The mass analyzer 142 always monitors gases present in the reactionchamber 110. When impurities are completely removed, that is, when thechlorine is not detected in the embodiment or when a concentration ofthe chlorine decreases to a level where no trouble is brought about, themass analyzer 142 sends a signal to the controller 150. In response tothe signal, the controller 150 controls the power supply unit 123, thevalve switch 132 and the reaction gas supply unit 161 to stop the plasmatreatment.

As above, since it is enabled to remove the chlorine ions remaining atthe substrate 109 formed of the polyimide film, this can preventcorrosion by residual ions, electrical failures such as ion migration orthe like which are to be caused if the IC is connected with the use ofACF in a state with the chlorine ions remaining. Moreover, since theplasma treatment of the substrate 109 is stopped when the removal of thechlorine is completed as described hereinabove, it is possible to removethe chlorine ions remaining at the substrate 109 while the effect ofoxygen ions on the substrate 109 is limited to a minimum. At the sametime, since the substrate 109 is formed of polyimide, as discussed inthe “BACKGROUND OF THE INVENTION”, the organic contaminant on thepolyimide surface can also be removed by the oxygen radicals and theoxygen ions, and functional groups such as C═O, COOH and the like areformed on the surface, whereby the bonding strength between thesubstrate and the ACF is improved.

The element within the substrate 109 that is controlled to emit from thesubstrate 109 is Br in the foregoing embodiments. However, the substratesurface treatment apparatuses 101 and 102 in the embodiments can beapplied to the other corrosive elements. Similarly, although the elementadhering to the substrate 109 is chlorine in the foregoing embodiments,the apparatuses 101 and 102 of the embodiments are applicable to theother elements as well.

In each of the above embodiments, suppressing the emission of theelement Br in the substrate 109, and removing the chlorine adhering tothe substrate 109 are described separately from each other. Needless tosay, however, suppressing the emission of substrate constituents andremoving impurities of the substrate may be carried out simultaneouslyby detecting a plurality of elements by the detecting device 140 such asthe above emission spectroscopic analysis device 141, the mass analyzer142, etc.

Although the reaction gas injected into the reaction chamber 110 isargon and oxygen respectively in the embodiments described above, thepresent invention is not restricted to the specific kind of gas, and forinstance, a mixed gas of argon and oxygen, hydrogen or nitrogen gas canbe utilized. It is to be noted, however, that the reaction gas should beselected in some cases from a view point of a relationship with thesubstance to be processed by the surface treatment, because it isnecessary to generate ions or the like effective for the substance to beprocessed by the surface treatment.

In each embodiment, the grounded opposed electrode 122 is arranged inthe reaction chamber 110. The grounded reaction chamber 110 may beadapted to function by itself as an opposed electrode, and the opposedelectrode 122 can be eliminated depending on the circumstances.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

1-14. (canceled)
 15. A substrate surface treatment method for executingsurface treatment to a circuit board arranged in a reaction chamber byions in plasma generated in the reaction chamber, the method comprising:detecting at least either whether or not components constituting thecircuit board are separated from the circuit board by the surfacetreatment, or whether or not impurities adhering to a surface of thecircuit board are removed by the surface treatment; and controlling on abasis of the detected information an energy of the ions in the plasma toreduce when the separation of components is detected to take place andthe surface treatment to end when the removal of impurities is detectedto end.
 16. The substrate surface treatment method according to claim15, wherein the control for reducing the energy of the ions in theplasma is performed by increasing a pressure in the reaction chamber.17. The substrate surface treatment method according to claim 15,wherein the detection of at least either whether or not componentsconstituting the circuit board are separated from the circuit board, orwhether or not impurities adhering to a surface of the circuit board areremoved is observed by an emission spectroscopic analysis.
 18. Thesubstrate surface treatment method according to claim 16, wherein thedetection of at least either whether or not components constituting thecircuit board are separated from the circuit board, or whether or notimpurities adhering to a surface of the circuit board are removed isobserved by an emission spectroscopic analysis.
 19. The substratesurface treatment method according to claim 16, wherein raising apressure in the reaction chamber is performed by closing a valvedisposed between the reaction chamber and a vacuum pump.
 20. Thesubstrate surface treatment method according to claim 15, wherein whenthe circuit board is formed of glass cloth epoxy resin, a component tobe detected is Br, and when the circuit board is formed of polyimidefilm, an impurity is Cl.
 21. A method of treating a surface of a circuitboard, the method comprising: providing a substrate surface treatmentapparatus having (a) a reaction chamber in which the circuit board isplaced for receiving the surface treatment by argon ions in plasmagenerated in the reaction chamber, (b) a plasma generating deviceincluding electrodes arranged in the reaction chamber and a power supplyunit for supplying electricity to the electrodes, (c) a reaction gassupply unit, connected to the reaction chamber, for supplying an argongas into the reaction chamber, (d) an exhaust port connected to thereaction chamber, and (e) a vacuum degree adjusting device, provided atthe exhaust port, for adjusting a degree of vacuum in the reactionchamber; generating plasma in the reaction chamber; treating the surfaceof the circuit board with argon ions in the plasma generated in theplasma chamber; detecting whether components of the circuit board havebeen separated from the circuit board by the surface treatment, orwhether impurities adhering to a surface of the circuit board have beenremoved by the surface treatment; controlling operation of the vacuumdegree adjusting device and reducing energy of the ions in the plasmawhen separation of the components from the surface of the circuit boardis detected, or terminating the surface treatment when substantiallycomplete removal of impurities is detected.
 22. The substrate surfacetreatment apparatus according to claim 21, wherein the detectingoperation is performed with a spectroscopic analyzer for conductingspectral observation of light generated by the plasma.
 23. The substratesurface treatment apparatus according to claim 21, wherein thecomponents of the circuit board include bromine or chlorine.
 24. Thesubstrate surface treatment apparatus according to claim 23, wherein thespectroscopic analyzer sends a signal to a controller when an emissionspectrum of bromine is observed.
 24. The substrate surface treatmentapparatus according to claim 21, wherein the detecting operationincludes observing the state of the plasma in the reaction chamber witha spectroscopic analysis device.
 25. The substrate surface treatmentapparatus according to claim 21, wherein the circuit board being treatedis formed of glass cloth epoxy resin, and the component being detectedis bromine.
 26. The substrate surface treatment apparatus according toclaim 21, wherein the energy of the ions in the plasma is reduced bydecreasing electric power supplied from a power supply unit to theelectrodes, and raising the pressure in the reaction chamber by drivinga valve of the vacuum degree adjusting device in a closing direction.27. The substrate surface treatment apparatus according to claim 21,wherein the circuit board being treated is formed of a polyimide film,and the impurity being detected is chlorine.